The invention relates to apparatus for extracting and analysing dust-laden gas samples, especially for attachment to an exhaust gas line of a heat exchanger in a suspended gas preheater, containing a gas extraction connection, a gas extraction probe associated with the gas extraction connection, an analyzer, a gas sample conveying pipe arranged between the gas extraction probe and the analyzer, and a switch valve in the gas sample conveying pipe.
In known extraction and analysis apparatus which can preferably be built onto an exhaust gas line of a cyclone preheater, one end of the gas sample conveying pipe is constructed in such a way that it can extend into the corresponding exhaust gas line of the preheater and thus forms the gas extraction connection, and a gas extraction probe can also be provided at this point. The gas sample conveying pipe is connected at its other end via an injector to the lower section of the exhaust gas line while being connected by a separate test gas line to the analyzer. The gas sample conveying pipe constantly provides a bypass for a quantity of sampled gas from which a sample can be supplied via the test gas line to the analyzer at predetermined times with at least one switch valve being switched appropriately in the lines.